In today's cellular architectures, it is difficult and expensive to introduce new services. The difficulty and expense may be attributed in large part to the monolithic architecture of switching centers, which do not allow for services to be introduced outside of the switch itself.
The IP Multimedia Subsystem (IMS) architecture addresses these limitations to some extent. According to current standards, an IMS architecture provides features to users through external application servers. An initial Filter Criteria (iFC) defines a set of Service Point Triggers (SPTs) to determine if a request should invoke a particular application server.
The IMS architecture, however, provides only limited capabilities through SPTs. Often, these SPTs are insufficient to provide advanced and efficient support for new terminal types and new services enabled by those terminals, such as presence, streaming video, and the like.
Thus, to facilitate the deployment of advanced features and new services, telephony developers need a platform that is flexible and not designed solely on existing and well-known capabilities and services. In particular, the shift from traditional cell phones to more sophisticated types of access terminals with richer user interfaces, improved processing and memory, and new types of media capabilities must be taken into account.